Air conditioning apparatus



Sept. 22, 1942. D.'w. McLENEGAN AIR CONDIETIONING APPARATUS Filed Nov. 29, 1941 1 .15. ull.

Invntor David W McLenegan,

His Attprney.

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Patented Sept. 22, 1942 UNITED STATES PATENT OFFICE AIR CONDITIONING APPARATUS David W. McLenegan, Caldwell, .N. 1., asslgnor to Generl Electric \Compauy, a corporation of New York Application November 39,1941, Serial No. 421,009 Y 'iclalms.

mizes noise. The casings may, if desired, be located in different portions of a building. Such apparatus frequently employs a motor-compressor unit completely enclosed by a housing and it is, therefore, necessary'to provide some arrangement for removing the heat generated within the housing by operation of the motor-and compressor. When there is an adequate supply of cooling water, the condenser may be enclosed within the housing together with a suitable coilfor cooling the air in the housing, cooling water being circulated both through the condenser and through the coil. In many localities, however, it is desirable to employ evaporative condensers which cannot readily be enclosed within the housing and some additional arrangement must be provided for removing 'heatgenerated within the housing.

It is an object of my invention to provide an air conditioning apparatus including a compression type refrigerating machine having a motor and compressor arranged in'a closed housing and an improved arrangement for removing heat generated by the apparatus within the housing.

Further objects and advantages of my invention will become apparent as the following description proceeds, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of my invention reference may be had to the accompanying drawing in which Fig. 1 is a sectional elevation view of an air conditioner embodying my invention and Fig. 2 is a view of a portion of the apparatus shown in Fig. 1 illustrating a modified form of my invention;

Briefly, the apparatus shown in the drawing comprises a casing divided into upper and lower compartments, the upper compartment containing a refrigerant evaporator and a fan or blower for circulating air over the evaporator and into the space to be conditioned, and the lower compartment comprising a closed housing contali 1- ing the com ressor and its driving motor. The

condenser is arranged externally ofthe casin (01. sz-c) v and is of the evaporative type denser coil and a water spray and a fan for cir-' culating air over the sprayed condenser surface. In order to, remove the heat generated by the motor and compressor within the housing, a refrigerant coil is connected in the refrigerant circuit of the refrigerating machine between the evaporator and the compressor and air is circulated over the coil within the housing. In order to maintain the temperature of the air in the housing below a predetermined value, a temperature control is provided to modify the operation of the thermostatic expansionvalve which controls the admission of refrigerant to the evaporof the refrigerating capacity of the machine for removing heat from the motor compressor hous- Referring now to the drawing. Fig. 1 I have shown an air conditioning comprising an upper casing II and a lower housing or casing II. The upper casing is provided with an air inlet I2 and an outlet grille "and a blower l4 driven by an electric motor ii. The blower is arranged to draw "air into the casing through the inlet l2 and over the surface of a finned coil evaporator It and thence out through the grille ll into the room to be conditioned. The lower casing ll forms with the bottom wall of the upper casing II a closed housing containing a refrigerant compressor l'l driven by a-motor II. The evaporator I5 and compressor I! are connected in a closed refrigerant circuit including a condenser l! and a liquid receiver 20; 'I'he condenser i9 is of the evaporative type and is arranged in a cooling tower or casing 2| through which air is circulated by operation of a blower 22. In order to spray water over the surface of the condenser i9 and provide evaporative cooling,

thereof constitutes a sump within which a body of water 23 is maintained, make-up water being admitted to the casing from a supply line 24 under control of a valve 25 actuated by a float 28. Water from the casing 2| is circulated by a pump 21 and sprayed over the surface of the condenser II by a spray head 2! providing a plurality of sprays 2!. 1

During the operation of,the refrigerating machine, refrigerant is compressed by the compressor l1 and delivered through va. connection 3| to the condenser II where the refrigerant is cooled and liquefied; the liquki refrigerant being delivered to the receiver 2.. From the receiver 20 the liquid refrigerant flows to the evaporator Ii comprising a conator. This arrangement thus employs a portion the casing 2| is formed so that the lower portion- 3| having a temperature responsive element or thermal bulb 33 connected in heat exchange with the evaporator on the outlet side thereof so that the temperature: of the bulb depends upon the temperature of the' refrigerant withdrawn from the evaporator. The refrigerant vaporized in the evaporator I6 is returned to thecompressor through a suction line 34.

In order to cool the air within the housing II, I provide a cooling coil or evaporator element 35 connected in the refrigerant circuit of the refrigerating machine between the evaporator l6 and the compressor I1, and the cooling capacity of the refrigerant withdrawn from the evaporator |6 through the suction line 34 is therefore available to cool air within the housing and constitutes the sole effective cooling capacity available for maintaining the temperature of the air below its predetermined desired maximum temperature. The air in the housing is circulated over the coil 35 by operation of a fan 36 driven by the motor I8.

Under certain load conditions it may happen that the setting of the thermostatic expansion valve 3| for normal operation will be such that insufficient cooling capacity remains in the re- 'frigerant supplied to the coil 35. In order'to assure suflicient cooling capacity to remove the heat generated by the motor and compressor within the housing II, I provide an electric heating element 31 arranged to supply heat to the bulb 33 and control the energization of the heater by athermostat comprising a spirally coiled bimetallic strip 38 arranged in the circuit of the heater 31 in series with the heater across supply lines 39 and 40 and arranged to vary the portion of a resistor 4| which shall be in series with the heater. The thermostatic expansion valve 3| is of the type commonly employed to control the amount of superheat of the vaporized refrigerant withdrawn from an evaporator, and the bulb 33 actuates an'element of the valve so that the valve tends to open upon a rise in temperature of applying heat ar cially to the evaporator l6 it is possible to open the valve 3| more than is necessary to supply the refrigerant required by e evaporator IE, and thereby the excess refrigerant is supplied to the coil 35. Under-normal conditions of operation the refrigerant supplied a will be saturated or nearly saturated vaporlzedrefrigerant.

to the coil 35 However, 'under extreme conditions of operation some liquid -refrigerant may be supplied to the coil 35.

During the operation of the refrigerating apparatus, should the temperature of the air within the housing rise, the bimetallic element 33 will move in a counterclockwise direction and reduce the amount of resistance in the circuit of the heater 31, and thereby increase the current flowing through the heater and raise the temperature of the bulb 33. This supplies an inv creased amount of cold or vaporizable refrigerant to the coil range the housing II- and the casing l indifferent parts of a building, andfor this purpose connecting pipe unions 42 and 43 in the liquid and suction lines, respectively, of the refrigerant the bulb. It follows that by 2,296,680 under control of a thermostatic expansion valve circuit so that sufficient refrigerant piping to extend the circuit and allow separation of the two units may be provided. The compartment II as shown is maintained closed by the bottom wall of the casing l0. Obviously when the two casings are separated, a plate or closure corresponding to the bottom wall of the casing I0 is secured in place over the top of the casing H.

In some installations adequate cooling of the housing may be obtained by securing the bulb 33 of the thermostatic expansion valve 3| to be responsive to the temperature of the refrigerant withdrawn from the coil 35 as shown in Fig. 2. This arrangement maintains substantially constant the amount of superheat in the vaporized refrigerant withdrawn from the coil 35 and assuresa suflicient cooling capacity for the coil 35, For some settings of the thermostatic expansion valve it may happen that after a long idle period of the compressor there will not be sufficient heat available in the machinery compartment to cause the thermal bulb 33 to open the expansion valve. In such cases it is desirable to'provide a heater 44 similar to the heater 31, and a thermostat 45 and variable resistor 45 for controlling I the energization of the heater 44. The thermostat 45 is constructed so that on a fall in temperature in the machinery compartment it will reduce the portion of the resistor 46 in the circuit and increase the energization of the coil 44 thereby supplying heat to the valve 33. Heat is thus available for opening the thermostatic expansion valve, even though the temperature of the machinery compartment has not risen to a value suiiiciently high to supply the heat. As the temperature of the compartment rises more re sistance will be placed in the circuitv and the energy supplied to the heater 44 will be reduced. With this arrangement the evaporator will operate at substantially full capacity very shortly after the condensing unit has been started.

During the operation of either of the systems illustrated, cooling capacity for reducing the temperature of the air in the machinery compartment is provided at all times without the necessity of arranging additional cooling-apparatus such as water coils within the machinery compartment,'

claims to cover all modifications within the spirit I and scope of my invention.

the refrigerant connections may be opened by dis- 2 What I claim as new and desire to secure by Letters Patent of the United States, is: g

1. A refrigerating system including a compressor and a condenser and an evaporator'connected in a clowd refrigerant circuit, a closed housing surrounding said compressor, means for circulating air within said housing and over said compressor, means including a refrigerant element arranged in said housing and connected in the refrigerant circuit of said system between said evaporator and said'compressor for cooling the air circulated in said housing to remove heat produced by the operation of said compressor, and temperature responsive means arranged to control the admission of refrigerant to said evaporator for maintaining the temperature of the air circulated over said compressor below a predetermined value.

frigerant circuit of said system between said evaporator and said compressor for cooling the air circulated in said housing to remove heat produced by operation of said compressonand a thermostatic expansion valve arranged to control the admission of refrigerant to said evaporator and having its thermal element secured in heat exchange relation with said refrigerant coil adjacent the outlet thereof for'controlling the admission of refrigerant to said evaporator.

3. A refrigerating system including a compressor and a condenser and an evaporator connected in a closed refrigerant circuit, a closed housing surrounding said compressor, means for circulating air within said housing and over said compressor, 'means including a refrigerant element arranged in said housing and connected in the refrigerant circuit of said system between said evaporator and said compressor for cooling the air circulated in said housing to remove heat produced by the operation of said compressor, a

thermostatic expansion valve arranged to control outlet side thereof, and means responsive to the temperature of the airin said housing for supplying heat to said thermal element to modify the operation of said expansion valve and to maincooling the air circulated in said housing to remove heat produced by the operation of said compressor, a thermostatic expansion valve for controlling the admission of refrigerant to said evaporator, said valve including a temperature responsive element secured in heat exchange relation with said evaporator on the outlet side thereof, a heater for supplying heat to said temperature responsive element and means responsive to the temperature of the air in said housing for varying the amount of heat'supplied by "said heater to modify the operation of said expansion valve for maintaining the temperature of the air in said housing below a predetermined value.

6. Air conditioning apparatus including a casv ing, means for circulating air through said casing -from said inlet to said outlet to cool the air,

tain the temperature of the air in said housing 7 below a predetermined value.

4. A refrigerating system including a compressor and a condenser and an evaporator connected in a closedrefrigerant circuit, a closed housing surrounding said compressor, means for circulating air within said housing and over said com pressor, means including a refrigerant element arranged in saidhousing and connected in the refrigerant circuit of said system between said evaporator and said compressor for cooling the air circulated in said housing to remove heat the outlet side thereof, anelec'tric heating element for supplying heat to said thermal element,

means providing a closed housing surrounding said compressor, means for circulating air within said closed housing, said condenser being arranged externally of said housing, means for cooling said condenser, means including a thermostatic expansion valve having a thermal bulb arranged to be responsive to the temperature of the refrigerant withdrawn from said evaporator for controlling the admission of refrigerant to said evaporator, a refrigerant coil connected in the refrigerant circuit of said refrigerating machine between said evaporator and said compressor for coolingthe air circulated within said housing, an electric heater for supplying heat to said thermal bulb, and thermostatic means dependent upon the'temperature of the air within said housing for varying the energization of said heater to vary the supply of refrigerant to said. refrigerant coil and tomaintain the temperature tion of air therethrough, 1a refrigerating ma-,

chine including a compressor and a condenser and an'evaporator connected inia closed refrigerant circuit, said evaporator being arranged in said casing, means for circulating air through and means responsive to the temperature of the air in said housing for controlling the energization of said heating element to modify the operation of said expansion valve for maintaining the temperature of the air in said housing below a predetermined value.

5. Air conditioning apparatus including a cas- .ing and means for circulating air therethrough, a

' nected in the refrigerant circuit of said refrig-' crating machine between said evaporator and refrigerating machine including a compressor and a condenser and an evaporator arranged in a closed refrigerant. circuit, said'evaporator being arrangedin said casing to cool the air circulated therethrough, means for cooling said con?- denser, a closed housing surrounding said compressor, means for circulating airwithin said housing, means including a refrigerant element arranged insaid housing and connected in the refrigerant circuit of said refrigerating machine between said evaporator and said compressor for said casing from saidinlet to said outlet to cool the air, means providing a closed housing sur-' rounding said compressor, means for circulating air within said closed houSing said condenser being arranged externally of said housing, means for cooling said condenser, a refrigerant coil consaid compressor for cooling the air circulated within said housing, means including a thermostatic expansion valve having a thermal bulb dependent upon the temperature of the air. with-.

in said housing for increasing the energization of said heater upon a fall of the temperature of the air within said housing below a predetermined value.

DAVID W. MCLENEGAN. 

